Fibular hemimelia (FH) is a disease of congenital limb deficiency characterized by the partial or total absence of the fibula. It represents the most common deficiency of long bones. The cause of FH disease remains unknown. It was first described by Gollier in 1698 (Coventry and Johnson, 1952). It has been estimated that there is approximately 1 in 50,000 cases live births (Florio et al., 1999). FH exhibits as a clinical spectrum from partial absence to complete absence of the fibular bone (Achterman and Kalamchi, 1979). The appearance of the developmental anomaly is not only absence of the fibula but also as follows: the femur is short, the tibia is bowed, the foot is deformed in an equinovalgus position, and presents tarsal coalition. Absence of lateral rays of the foot may be seen in patients with severe FH disease.
Proximal femoral focal deficiency (PFFD) is a rare congenital anomaly characterized by abnormal development of the proximal femur (Gillespie et al., 1983). Symptoms range from an absence of the entire femur and abnormal development of the pelvis to a hypoplastic femur of normal configuration. The disorder is unilateral in 90% of the cases. It is commonly linked with the absence or shortening of leg bone and the absence of a kneecap. The lower extremity is abducted, flexed and externally rotated through the upper femur. Other features of PFFD include the dislocation or instability of the joint between the femur and the kneecap, a shortened tibia or fibula, and foot deformities.
Tarsal coalition (TC) is a fibrous, cartilaginous, or bony connection of two or more tarsal bones. Foot pain is the typical symptom. Although usually developing during adolescence, the onset of aching pain in the foot tends to correlate with age at which the coalition bar ossifies (Kulik et al., 1996). Classic presenting symptoms are that the peroneal spastic flat foot, with the hindfood held in eversion and spasm of the peroneals noted on attempts to invert the foot. The most common tarsal coalitions involve the calcaneonavicular and talocalcaneal joints.
Humeroradial synostosis (HRS) is rare congenital abnormality in which there is fusion between humerus and radius. HRS is categorized by deformity. Class I is associated with ulnar ray hypoplasia and elbow extension. Class II synostoses are not associated with hypolasia where the elbow is flexed (McIntyre et al., 2002). HRS often causes little functional disability. Both sporadic and genetic cases of humeroradial synostosis are encountered.
The etiology of fibular hemimelia (FH), proximal femoral focal deficiency (PFFD), tarsal coalition (TC) and humeroradial synostosis (HRS) disease are unclear, but genetic and environmental factors are generally acknowledged. Understanding the pathological mechanisms of these diseases will help the prevention and treatment of the diseases.